by Kastro
Paper/Archive/CVE-2026-53581

CVE-2026-53581

opnsense core — ntp: write path traversal

EPSS 0.5%public exploitCVSS 9.0
critical.is priorityof 100
45
CVSS 9.0 (CNA)9.0 / 10 × 3027.0Not in CISA KEV+300.0EPSS percentile 40.9.409 × 208.2Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.9 of opnsense/core and version 26.4_20 of BE/opnsense/core, a path traversal vulnerability in the NTP configuration module allows an attacker to overwrite arbitrary files on the system as the root user. By manipulating the GPS or PPS serial port parameter, an attacker with access to the NTP configuration can escape the intended directory and force the system to write user-controlled data to any file on the filesystem. Version 26.1.9 of opnsense/core and version 26.4_20 of BE/opnsense/core patch the issue.

Affected

ProductAffectedFixed inSource
core< 26.1.9–CNA
core< 26.4_20–CNA

Scores by source

GitHub_M (CNA)9.0CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:H
CISA ADPSSVCExploitation: poc · Automatable: no · Technical impact: partial

References

exploitgithub.com/opnsense/core/security/advisories/GHSA-872g-g543-j37m